This invention relates generally to a television set having a matrix type display comprised of liquid crystal display elements and more particularly, to a matrix television set wherein signals for horizontal and vertical scannings are obtained from one oscillator circuit. Conventional television sets using a cathode ray tube for display are generally well known. The circuitry is subject to integration as, for example, in "An integrated synchronizing circuit for TV receivers," pp 227-233 of IEEE transactions BTR-16 1970 No. 3.
In a synchronizing circuit according to the prior art, vertical and horizontal synchronizations are effected separately and two oscillator circuits are required. The oscillation frequency of the horizontal synchronizing circuit is equal to the frequency of the horizontal scanning signal, that is, approximately 16 kilohertz. The oscillation frequency of the vertical synchronizing circuit is 60 Hz in the United States and Japan.
A matrix television set needs one additional ocillator for generating a shift clock pulse. Thus, the synchronizing circuits of prior art matrix television set have the following disadvantages. First, there is a need for three oscillators and it is difficult to provide a circuit in the form of an integrated circuit, in particular, in the form of a C-MOS integrated circuit.
Further, in a television set using a cathode ray tube, a phase comparator of the AFC circuit is easily constructed by using a serrated waveform because the scanning deflection is effected by the serrated waves. On the other hand, a matrix television set requires a circuit system of good efficiency without using a serrated wave.
Additionally, power consumption of the synchronizing circuit in the prior art matrix television sets is large.
What is needed is a synchronizing circuit for a matrix television set which is simple in construction, can be formed as an integrated circuit and consumes little power.